[Patent Literature 1] JP 2012-54830 A (US 2012/0051241 A)
For example, Patent Literature 1 discloses a communication system to wake up individually communication nodes that are under sleep mode. The communication system uses a communication frame that contains an activation pattern area and an assignment pattern area. A subject communication node, which is any one of the plurality of communication nodes, includes a transceiver with an activation frame detection section. When determining a received communication frame as an activation frame directed at the subject communication node itself, the activation frame detection section generates a wake-up signal, thereby permitting a microcomputer of the subject communication node to execute a wake-up process. The received communication frame is determined as an activation frame directed at the subject communication node itself under condition that (i) the activation pattern area contains an activation-used ID having an area length up to a border point, the area length being longer than an activation length, and, simultaneously, (ii) the assignment pattern area contains an assignment code assigned to the subject communication node.
The communication system in Patent Literature 1 requires a subject communication node to previously store an assignment code that is assigned to the subject communication node itself in a memory (assignment pattern configuration circuit) inside of an own transceiver. However, Patent Literature 1 does not specifically describe how to store the assignment code.
For instance, a communication node includes a control portion (i.e., microcomputer) and a transceiver. The control portion generates data that is to be transmitted and processes data that is received. The transceiver transmits the data generated by the control portion to the communication bus as a communication frame, and receives data that is sent out as a communication frame from a different communication node.
The present Inventor supposes a case that the control portion may be used to write an assignment code in a memory inside of the transceiver. If this case uses a direct access from the control portion to the memory for write-in process, additional configuration may be necessary. That is, an interface may be necessary in the transceiver for receiving a signal transmitted from the control portion to the memory, such as a notice signal of writing request of a code or a code data indicating the code; a dedicated signal line may be necessary for connecting between the interface and the control portion. This may increase the number of signal lines or the number of ports of the control portion, leading to the increase the body magnitude of the communication node as well as the increase of costs.